Windows is likely to be running out of desktop heap.
Confirm this to be the case
by looking in the log for the condor_schedd daemon
to see if condor_shadow daemons are immediately
exiting with status 128.
If this is the case, increase the desktop heap size.
Open the registry key:

The SharedSection value can have three values separated by commas.
The third value controls the desktop heap size for non-interactive desktops,
which the HTCondor service uses.
The default is 512 (Kbytes).
60 condor_shadow daemons consume about 256 Kbytes,
hence 120 shadows can run with the default value.
To be able to run a maximum of 300 condor_shadow daemons,
set this value at 1280.

Reboot the system for the changes to take effect.
For more information,
see Microsoft Article Q184802.

This work supported in part by NSF grants MCS-8105904, OCI-0437810, OCI-0850745, and/or ACI-1321762. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Site built using CVSTrac.